Perfusion catheters and related methods

ABSTRACT

This patent document discloses perfusion catheters and related methods for treating complications related to CTO interventions or dilating a vessel occlusion while maintaining a passage through the treated vessel segment. A perfusion catheter can include an inflatable balloon coiled in a helical manner around a central axis into a series of windings. An inner surface of the series of windings, when inflated, can define a passage through the inflatable balloon. A catheter can also include an elongate shaft extending from a proximal portion to a distal portion, having an inner surface that defines a lumen for providing inflation fluid to, or withdrawing inflation fluid from, a distal end of the inflatable balloon. A catheter can further include a guidewire support tube including a lumen, separate from the lumen from the elongate shaft and the passage through the inflatable balloon, for receiving a guidewire.

CLAIM OF PRIORITY

This non-provisional patent document is a continuation of U.S. patentapplication Ser. No. 16/414,921, entitled “PERFUSION CATHETERS ANDRELATED METHODS” and filed May 17, 2019, which claims the benefit ofpriority under 35 U.S.C. § 119(e) to U.S. Provisional Patent ApplicationSer. No. 62/701,362, entitled “PERFUSION CATHETERS AND RELATED METHODS”and filed on Jul. 20, 2018, each of which is herein incorporated byreference in its entirety.

TECHNICAL FIELD

The subject matter of this patent document relates to the field ofmedical devices. More particularly, but not by way of limitation, thesubject matter relates to catheters and related methods for sealing avessel perforation or dissection or dilating a vessel occlusion.

BACKGROUND

A severe or chronic total occlusion (CTO) is a vessel blockage thatprevents blood flow beyond the occlusion. Chronic total occlusions mostoften occur in coronary and peripheral arteries and result fromatherosclerosis.

A procedure for treating CTOs is percutaneous transluminal angioplasty.

During an angioplasty procedure, access to a desired blood vessel isobtained and a guidewire is introduced into the blood vessel. Theguidewire is maneuvered into place, including being passed into andthrough the occlusion, and acts as a guide for positioning a subsequenttreatment device used to dilate or otherwise treat the vessel occlusion.The treatment device can be advanced over the guidewire so that itsdistal portion is positioned within the occlusion. A dilatation balloonat the distal portion of the treatment device can then be inflated toapply radial pressure to the occlusive material and adjacent inner wallportions of the vessel, thereby clearing the occlusion to enable betterblood flow.

Overview

The present inventors recognize that CTOs are one of the mostchallenging lesion subsets in interventional cardiology to treat due totheir established occlusive structure. Complications related to CTOinterventions include vessel wall perforation and dissection. If nottreated without delay, blood hemorrhaging through the perforation ordissection can lead to death of the patient within minutes.

The present inventors also recognize that sealing of the vesselperforation or dissection using conventional balloon catheters causescomplete interruption of blood flow within the damaged vessel while thecatheter's balloon is inflated. Keeping the balloon inflated for anextended period can risk damage to bodily regions nourished by thevessel-regions already weakened by insufficient blood supply. Forexample, prolonged dilations of several minutes may need to be employedto effectively treat a perforation. Yet, most adults are only able towithstand non-perfusion dilation of 30-60 seconds without significantside effects.

The present inventors further recognize that after treating a vessel,the catheter balloon may not sufficiently deflate, making it difficultor even impossible to pull the balloon back into the guide catheter andremove it from the patient. The inventors particularly recognize thatfluid remaining in the balloon is often pushed distally as the balloonis pulled proximally into the guide catheter, thereby trapping fluid inthe balloon and preventing complete deflation, which also increases thelikelihood of puncturing the balloon.

The present perfusion catheters can be quickly and easily deployed,inflated, and deflated in a damaged vessel. The catheters can alsoprovide a passage (or flow lumen) formed upon inflation of its balloon.A perfusion catheter can include a balloon formed of an inflatable tubeand an elongate shaft having a lumen for providing inflation fluid to,or withdrawing inflation fluid from, the balloon. The inflatable tubecan be coiled in a helical manner around a central axis into a series ofwindings. Adjacent windings can be stacked against and bonded to eachother or laterally spaced, and an inner surface of the series ofwindings, when inflated, can define the passage. The elongate shaft canbe eccentrically attached to a distal portion of the balloon and itslumen can be in fluid communication with the interior of the inflatabletube. The inflatable tube can include two different polymer tubes, oneslightly smaller than the other. The smaller, inner tube can be formedfrom a polymer having sufficient radial stiffness to resist collapse orbursting when exposed to inflation pressures, and the larger, outer tubecan be formed from a polymer configured to exhibit adhesive propertieswhen heated.

The present methods for sealing a perforation or dissection or dilatingocclusive material can include inserting a guidewire into a blood vesseland advancing the guidewire to or across a treatment site, passing aperfusion catheter over the guidewire until a distal portion of theperfusion catheter is positioned near or within the treatment site, andinflating a balloon of the perfusion catheter. Inflating the balloon caninclude inflating a series of windings of helically-wound tubing, whichmay be contacting or laterally spaced. The balloon, upon inflation, canmove from a deflated configuration to an inflation configuration atwhich an outer surface of the balloon can engage a wall of the bloodvessel and an inner surface of the balloon can define a passage. Thepassage can allow a flow of bodily fluid, such as blood, through theperfusion catheter. Optionally, the method can include passing atreatment device at least partially through the passage. Aftertreatment, the balloon can be deflated in a distal-to-proximal directionand removed through the guide catheter.

Objects of the present perfusion catheters and related methods include,among others:

1. Sealing a vessel perforation or dissection by blocking the injuryfrom inside the vessel for an extended period of time while maintaininga sufficient flow of blood through a treated vessel segment;

2. Dilating a vessel occlusion for an extended period of time whilemaintaining a sufficient flow of blood through a treated vessel segment;

3. Delivering or receiving one or more treatment devices while sealing avessel perforation or dissection or dilating a vessel occlusion; and/or

4. Cleanly removing all treatment devices.

These and other examples and objects of the present perfusion cathetersand related methods will be set forth in the following DetailedDescription. This Overview is intended to provide non-limiting examplesof the present subject matter—it is not intended to provide an exclusiveor exhaustive explanation. The Detailed Description below is included toprovide further information about the present perfusion catheters andrelated methods.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like numerals can be used to describe similar featuresand components throughout the several views. The drawings illustrategenerally, by way of example but not by way of limitation, variousembodiments discussed in the present patent document.

FIG. 1 illustrates a schematic view of a guidewire advanced through apatient's vasculature and unable to penetrate an end cap of an occlusionwithin a vessel.

FIG. 2 illustrates a schematic view of a distal portion of a treatmentdevice dilating an occlusion within a vessel segment, such dilationcausing dissection of the vessel's wall.

FIG. 3 illustrates a side view of a perfusion catheter, as constructedin accordance with at least one embodiment.

FIG. 4 illustrates an enlarged side view of a distal portion of aperfusion catheter including a dedicated guidewire lumen, as constructedin accordance with at least one embodiment.

FIG. 5 illustrates an enlarged cross-sectional view of a distal portionof the perfusion catheter taken along line A-A of FIG. 4.

FIG. 6 illustrates an enlarged cross-sectional view taken along line B-Bof FIG. 5.

FIG. 7A illustrates an enlarged cross-sectional view taken along lineC-C of FIG. 5.

FIG. 7B illustrates an enlarged cross-sectional view taken at detail ABof FIG. 7A.

FIG. 7C illustrates an enlarged cross-sectional view taken at detail AAof FIG. 7A.

FIG. 8 illustrates an enlarged side view of a distal portion of theperfusion catheter shown in FIG. 4, with its balloon in a deflatedconfiguration within a vessel segment.

FIG. 9 illustrates an enlarged side view of a distal portion of theperfusion catheter shown in FIG. 4, with its balloon in an inflatedconfiguration within a vessel segment.

FIG. 10 illustrates an enlarged side view of a distal view of a distalportion of a perfusion catheter including a dedicated guidewire lumen,as constructed in accordance with at least one embodiment.

FIG. 11 illustrates a cross-sectional view taken along line D-D of theextruded tubing shown in FIG. 10.

FIG. 12 illustrates a mandrel for manufacturing a balloon of a perfusioncatheter, as constructed in accordance with at least one embodiment.

FIG. 13 illustrates a side view of an elongate shaft of a perfusioncatheter, as constructed in accordance with at least one embodiment.

FIG. 14 illustrates a cross-sectional view taken along line E-E of theelongate shaft shown in FIG. 13.

FIG. 15 illustrates a method of using a present catheter to navigatethrough vasculature, as constructed in accordance with at least oneembodiment.

The drawing figures are not necessarily to scale. Certain features andcomponents may be shown exaggerated in scale or in schematic form andsome details may not be shown in the interest of clarity andconciseness.

DETAILED DESCRIPTION

With the advancement of medical devices and increased training,clinicians are treating CTOs using angioplasty techniques more than everbefore. The present catheters and methods provide the clinicians with ameans to treat complications related to CTO angioplasty interventions orto dilate a vessel occlusion while maintaining a passage through thetreated vessel segment. The present catheters and methods also providethe clinicians with a means to safely and effectively remove allinterventional devices after treating a CTO. While the catheters andmethods are primarily discussed in relation to treatment of coronaryarteries, they may also be useful in other blood vessels throughout thebody including peripheral arteries and veins.

FIGS. 1 and 2 provide examples of complications related to CTOangioplasty interventions in which the present perfusion catheters andrelated methods can be beneficial. In patients suffering from a CTO,successful treatment of the occlusion can be challenging. A factor thatcan determine whether a treating clinician can successfully treat theocclusion is the clinician's ability to advance a guidewire from a firstside of the occlusion to a second side of the occlusion. In someinstances, such as when the natural lumen 102 of a blood vessel 104 istotally occluded by hard plaque 106 (e.g., calcified atheroscleroticplaque), the guidewire 108 cannot cross the occlusion and, in responseto a continued proximally-applied pushing force 110, its distal portion112 may deviate to, and perforate 114, an adjacent vessel wall 116, asshown in FIG. 1.

In other instances, such as when the occlusive material 206 is soft orwhere the occlusion has a tiny opening, the guidewire 208 can be forcedthrough the occlusive material and allowed to remain within the naturallumen 202 of the blood vessel 204. A treatment device, such as a ballooncatheter 218, can be guided over the guidewire 208 to the occlusion sitewhere it can be used to carry out dilation treatment. Mechanicaldilatation of the vessel 204 with the balloon catheter 218 can beassociated with plaque fracture, intimal wall splitting, and localizedmedial dissection. Dissection 220, if it occurs, may propagate into themedia and through the adventitia (the outermost layer of the vesselwall), resulting in another form of coronary perforation as shown inFIG. 2.

Perforations and dissections are serious complications for acatheterization laboratory because of their associated morbidity andmortality rates and, for this reason alone, their management andtreatment is important and should be initiated quickly. A first step inmanagement and treatment can be the placement of a balloon to seal theperforation or dissection. Prolonged balloon inflation may successfullyseal the perforation or stop the propagation of the dissection and canprovide time to prepare and implant a covered stent, if needed.

The present perfusion catheter 300 can be used in cases where there is avessel perforation or dissection to be treated and further in caseswhere there is occlusive material to be dilated. The catheter 300 can beadvanced through a guide catheter and directed through vasculature fortreatment of the vessel wall injury using a guidewire and optionally aplacement catheter. The perfusion catheter 300 can include a proximalmanifold 324 for coupling with an inflation syringe, an elongate shaft326, and a distal balloon 328 to seal the perforation or dissection ordilate the occlusive material.

The elongate shaft 326 can serve two primary purposes. First, theelongate shaft 326 can transmit forces applied by a clinician to eitheradvance or retract the perfusion catheter 300, and specifically theballoon 328, during an angioplasty or sealing procedure. By manipulatingthe elongate shaft 326, the balloon 328 can be inserted into and passedthrough a guide catheter and out the distal portion of the guidecatheter to a perforation or dissection to be sealed or an occlusion tobe dilated. Second, the elongate shaft 326 includes a lumen 330 forproviding inflation fluid to, or withdrawing inflation fluid from, theballoon 328. The lumen 330 of the elongate shaft 326 can be in fluidcommunication with the manifold 324, couplable to an inflation syringe,at its proximal portion 332, and it can be in fluid communication withthe interior of the balloon 328 near its distal portion 334.

The elongate shaft 326 can be eccentrically attached to a distal portion336 of the balloon 328 and can extend proximally for clinicianaccessibility outside the guide catheter. The elongate shaft 326 can beattached to the balloon 328 by wrapping the balloon 328 about theshaft's intermediate 338 or distal 334 portions and affixing it thereto.In an example, the elongate shaft 326 is attached to the distal portion336 of the balloon 328 for a minimum of 5 mm.

The embodiment of FIG. 3 illustrates that the balloon 328 can be formedfrom an inflatable tube 340 coiled in a helical or spiral manner arounda central axis into a series of windings 342 (or loops), withconsecutive or adjacent windings 342. The windings 342 may be stackedagainst and contacting each other with substantially no spacetherebetween, which can ensure the windings 342 act as a unit.Alternatively, the windings 342 may be spaced apart such that adjacentwindings do not contact each other. Spaced windings 342 may be preferredfor non-coronary applications, which may involve positioning the balloon328 in veins of greater diameter. The inner surfaces of the windings 342can define a passage 344 through the open center of the helix when thecoiled balloon 328 is inflated. The passage 344 can extend the fulllength of the balloon 328 to permit blood or other fluid to perfuse (orflow) therethrough, which is important since cutting off blood supplyfor extended periods of time is undesirable. When the balloon 328 isdeflated, it can collapse or flatten into a low profile configuration,which may comprise one or more folds that wrap around the distal portion334 of the elongate shaft 326. An elastic sheath can optionally bedisposed around the balloon 328 and be utilized to reduce the collapsedprofile of the deflated balloon so that it can be more easily insertedor removed from a patient.

Because the passage 344 is created by the balloon 328, blood flow ispermitted through the passage 344 and the overall perfusion catheter 300can be kept to a minimal size. This physical attribute allows thecatheter 300 to be of a small diameter when it is inserted into thepatient's body and maneuvered to the desired position, yet provides arelatively large blood flow passage when the balloon 328 is inflated.

FIG. 4 illustrates an enlarged side view of a distal portion of aperfusion catheter 400, as constructed in accordance with at least oneembodiment. The catheter 400 can be provided with a guidewire lumen 452separate from a passage 444 defined by windings 442 of a balloon 428 andseparate from a lumen 430 of an elongate shaft 426 for providinginflation fluid to, or withdrawing inflation fluid from, the balloon428. In the example shown, the windings 442 are stacked against eachother, but in additional embodiments, the windings can be spread apart,such that a lateral space 443 is defined between them. The guidewirelumen 452 can have a length 454 approximately equal to, or slightlylonger than, the length 448 of the passage 444 and can be positionedtherein. An outer surface of a guidewire support tube 456 forming theguidewire lumen 452 can contact inner surfaces of the windings 442 ofthe balloon 428 and can optionally be inset in these inner surfaces.Polymers of the guidewire support tube 456 and the balloon 428 can beconfigured to adhere to each other upon application of heat treatment. Aproximal end 457 of the guidewire support tube 456 may defined a skivedentry configured to receive the guidewire in some examples. In variousexamples, the proximal end 457 may define a length 453 ranging between 2mm and 5 mm, inclusive. In some embodiments, the elongate shaft 426 andthe proximal end 429 of the balloon 428 may be fused together along adistance 463 of the guidewire lumen 452.

A distal end 436 of the balloon 428 is fluidly coupled with a distal end431 of the lumen 430 of the elongate shaft 426, such that inflationfluid is added and removed at the distal end 436 of the balloon. Theballoon 428 can be helically coiled proximally from its distal end 436,and a proximal end 429 of the balloon 428 may comprise a tail portionwrapped around the inflation lumen 430, thereby sealing the proximal end429. Proximal wrapping of the balloon 428 may be implemented withoutheat shrinking or adhesive application in various implementations.Because the proximal end 429 of the balloon 428 can be sealed andinflation fluid can only be removed via its distal end 436, deflation ofthe balloon 428 may occur in a distal-to-proximal direction, in thedirection of the arrow toward a guide catheter 455. Accordingly, whenthe catheter 400 is deflated and pulled proximally back into a guidecatheter, the inflation fluid may not become trapped or sequestered inany portion of the balloon 428. This facilitates effective and saferemoval of the catheter 400 from a treatment site, for example bydecreasing the cross-sectional diameter of the deflated balloon.Complete deflation may also reduce the risk of puncturing or tearing theballoon 428 upon its reentry into the guide catheter 455. In examples, amaximum distance 433 of about 2 mm of the balloon may not be reflowed.

The guidewire lumen 452 can be designed to receive and facilitatetracking of a previously positioned guidewire having its distal portionin position near or across a treatment site. The perfusion catheter 400,and specifically the guidewire support tube 456, can be slid over theguidewire and advanced to the treatment site. An inner diameter of theguidewire support tube 456 can be sized to be advanced over a 0.36 mm(0.014 in) guidewire, for example. An atraumatic distal end portion 458culminating in a tapered tip 459 can be disposed at a distal tip of theguidewire support tube 456 to prevent the perfusion catheter 400 fromperforating a blood vessel during deployment and use. In variousexamples, a proximal portion of the distal end portion 458 can bedistally offset by a distance 465 ranging from about 0.1 mm-5 mm. Sincethe guidewire support tube 456 can be short compared to the totallengths of the catheter 400 and the guidewire, the use of the guidewiresupport tube 456 as a guide permits rapid exchange of the catheter 400over the guidewire.

One or more radiopaque markers 460 can be placed on the guidewiresupport tube 456 or the elongate shaft 426 proximal or distal to theballoon 428. These markers 460 can facilitate proper placement of theballoon 428 relative to a vessel wall injury prior to its inflation andcan be any suitable radiopaque material detectable through the use ofx-ray or fluoroscopy. Materials such as the platinum series of metals(e.g., platinum or palladium), gold, silver, iridium, or tantalum can beused as the markers. Certain stainless steels can also be suitable foruse as markers. Alternatively, the polymer used in portions of theperfusion catheter 400 can be radiopaque or made so by addition offiller such as barium sulfate, bismuth trioxide, bismuth carbonate,tungsten, tantalum, or the like.

FIG. 5 illustrates a cross-sectional view of a catheter 500 (taken alongline A-A of FIG. 4). As shown, the inflation lumen 530 of the elongateshaft 526 can longitudinally span the length of the balloon 528, suchthat each of the plurality of windings 542 covers the elongate shaft526. The guidewire support tube 556 can extend for a distance beyond thedistal end of the elongate shaft. In the embodiment shown, the distalend portion 558 of the guidewire support tube 556, including the taperedtip 559, can define a length 561 of about 3 mm. The length 561 may varyin examples, ranging from about 1 mm to about 6 mm, about 2 mm to about5 mm, or about 1.5 mm to about 4.5 mm. The diameter or width 563 of thedistal end portion 558 may also vary. In various embodiments, themaximum width of the distal end portion may be about 0.038 in. Theminimum width may be adjustable, provided the width is sufficient toaccommodate a guidewire for various applications. In examples, the width563 may range from about 0.01 in to about 0.05 in.

FIG. 6 illustrates a cross-sectional view of an inflated balloon 628 anda guidewire support tube 656 and elongate shaft 626 extendingtherethrough, taken along line B-B of FIG. 5. The guidewire support tube656 and the elongate shaft 626 can be inset or embedded within a radialportion of the inflatable tube comprising the balloon 628, leaving theinternal passage 644 unobstructed upon inflation of the balloon 628. Inexamples, the balloon windings can be bonded directly to the guidewiresupport tube 656 for the full length of the balloon, such that theguidewire lumen 652 and inflation lumen 630 are fully enveloped by theballoon. In some embodiments, an outer surface of the elongate shaft 626and the distal end of the inflatable balloon 628 can be affixed by aheat treatment process such that the shaft's lumen is in fluidcommunication with an interior of the balloon.

The inner diameter 657 of the inflated balloon 628 can accommodatepassage of various treatment devices, e.g., stents, therethrough. Theinner diameter 657 may be about 3 mm in some examples, and can range inadditional implementations from about 1 mm to about 6 mm, about 2 mm toabout 5 mm, or about 1.5 mm to about 4.5 mm. The outer diameter 659 canalso vary, depending for example on the diameter of a vessel at thetargeted treatment site. In various embodiments, the outer diameter 659can range from about 2 mm to about 8 mm, about 3 mm to about 6 mm, about3.5 mm to about 5 mm, about 3.75 mm to about 4.25 mm, or about 4 mm.

FIG. 7A illustrates a cross-sectional view of a catheter 700, takenalong line C-C of FIG. 5. As shown, the elongate shaft 726 and guidewiresupport tube 756 can be positioned adjacent to each other, each embeddedwithin the balloon 728. FIG. 7B provides an enlarged view of detail AB,showing where the fluid connection between a distal portion 734 of theelongate shaft 726 and a distal portion 736 of the balloon 728 can beestablished, proximal to the distal end portion 758 of the guidewiresupport tube 756. FIG. 7C provides an enlarged view of detail AA,showing the proximal end 729 portion of the balloon, which in theexample shown, comprises a tail portion wrapped around the inflationlumen 730.

FIG. 8 illustrates a perfusion catheter 800 in a blood vessel 804 of apatient. The catheter 800, and specifically a balloon 828 of thecatheter, can be introduced and advanced within the blood vessel 804 ina low profile, unexpanded configuration. In this configuration, theballoon 828 is in a relaxed, folded, or crushed configuration and doesnot significantly increase the overall diameter of a distal portion ofthe catheter 800 such that it can be inserted into the patient andguided through the patient's vasculature to the desired treatment site.

Once at the treatment site, the balloon 928 can be inflated asillustrated in FIG. 9. Fluid under pressure can be supplied to theballoon 928 through an inflation lumen 930 of an elongate shaft 926,thereby expanding the balloon 928 toward a wall 916 of the blood vessel904, such as for sealing, opening, or otherwise treating it. Wheninflated, the balloon 928 can impinge upon or engage the vessel wall 916at the treatment site at pressures of 2 atm-20 atm, for example, yetblood can be allowed to flow through the passage 944 defined by theballoon's windings 942. Since the passage 944 created through thewindings 942 is relatively large compared to the size of the vessel 904,the interruption of blood flow through the vessel is minimized and theperfusion catheter 900 is capable of prolonged inflation for temporaryhemostasis in coronary perforations or dissections.

Beyond allowing for fluid flow, the passage 944 of the balloon 928 canbe adapted to slidably receive a treatment device (e.g., a smallerdiameter balloon catheter, stent catheter, guidewire support catheter,or guidewire). The balloon 928 can include any number of windings 942 ina number of sizes and configurations depending upon the particulartreatment site, procedure and/or patient. Increasing the number ofwindings 942 in the balloon 928 can increase the ability of the balloon928 to maintain a dilated state of an occlusion. The passage 944 canhave a diameter 946 ranging from 2 mm-6 mm and can extend 10 mm-50 mm inlength 948, for example. The diameter 946 of the passage 944 can besufficiently large to permit entry of a stent catheter. The presentinventors recognize that plaque has a tendency to return to its originalform and restrict passage. This restenosis, if it occurs, can occur asquickly as a few minutes. The perfusion catheter 900 allows the stentcatheter to be delivered through the catheter while the balloon 928dilates the occlusion. In this way, there can be minimal time betweenocclusion dilation and placement of a stent. The diameter 946 of thepassage 944 can be sufficiently large to receive a guidewire supportcatheter to help pre-dilate or otherwise establish a pilot openingthrough the occlusion, or to receive the distal portion of a retrogradeguidewire that is funneled into the passage 944 as a result ofengagement between an outer surface 950 of the balloon 928 and thevessel wall 916.

When the procedure is completed, the balloon 928 can be deflated byapplying vacuum to a proximal manifold coupled with the inflation lumen930 of the elongate shaft 926. The entire perfusion catheter 900 canthen be removed.

FIGS. 10 and 11 respectively illustrate side and cross-sectional viewsof extruded tubing 1040 for use in a balloon of a perfusion catheter, asconstructed in accordance with at least one embodiment. The extrudedtubing 1040 can have a uniform outer diameter along its length 1062 orcan have a larger diameter along a majority of its length and tapereddown on its proximal 1064 and distal 1066 portions. The length 1062 ofthe extruded tubing 1040 can range from 40 cm-120 cm before being coiledin a helical or spiral manner into a series of windings.

The coiled shape of the balloon can be maintained by causing adjacentwindings to adhere to one another, in some examples, and the integrityof the balloon can be internally provided within each winding. Thesequalities can be accomplished by coextruding a combination of nestedpolymers which, after winding of the coil, can be heat treated to allowadjacent coils to stick to each other. In the example of FIG. 11, theextruded tubing 1140 is formed by coextruding two different polymertubes 1168, 1170 (or layers), one slightly smaller than the other. Thecoextrusion process can eliminate seams, which are found in existingballoon designs, form tight bonds, and create a balloon using a reducednumber of manufacturing steps. Alternatively, the smaller tube 1168 canbe inserted inside the larger tube 1170 post-extrusion.

The smaller, inner tube 1168 can be formed from a polymer havingsufficient radial stiffness to resist collapse or bursting when exposedto inflation pressures, and the larger, outer tube 1170 can be formedfrom a polymer configured to exhibit adhesive properties when heated andcompliant properties when used within the body. In some examples, theadhesive properties of the outer tube 1170 can allow adjacent windingsto adhere to one another. The use of a compliant material for the outertube 1170 can enable the balloon to conform to a vessel wall at the siteof a perforation or tear, so that a substantial portion of the balloon'souter surface can be compressed against the vessel wall, or at the siteof an occlusion that can benefit from being dilated. In variousexamples, the inner tube 1168 can include polyethylene terephthalate(PET) or PEBAX polyether block amides (which are available from Arkema)having an outer diameter of 0.2 mm-0.28 mm and an inner diameter of 0.12mm-0.18 mm, and the outer tube 1170 can include HYTREL polyesterelastomer (which is available from E.I. du Pont de Nemours and Company),PEBAX, or nylon having an outer diameter of 0.28 mm-0.36 mm and an innerdiameter of 0.20 mm-0.28 mm. The inner 1168 and outer 1170 tubes caninclude polymers having different melting or softening temperatures,with the inner tube 1168 including the polymer with the higher meltingtemperature. The inner 1168 and outer 1170 tubes can include the same orsimilar polymers, with the polymer of the inner tube 1168 beingcross-linked for strength and with the polymer of the outer tube 1170not being cross-linked.

FIG. 12 illustrates a mandrel 1272 for coiling extruded tubing in ahelical manner around a central axis into a series of windings to form aballoon. The extruded tubing can be wrapped in a proximal directionabout the mandrel 1272, which includes a shape of the intended profileof the balloon. After being wrapped onto the mandrel 1272, the extrudedtubing can be pressurized or inflated and adjacent windings can be heatset in order to ensure that they adhere to one another and the balloonmaintains its coiled shape. For example, heat setting the coiledconfiguration of the balloon can include causing the outer surface ofadjacent windings of the extruded tubing to adhere to one another viaheating the tubing or the mandrel 1272. The extruding tubing can then becooled to room temperature. In additional examples, adjacent windingsmay not be heat set in order to ensure that the windings remainlaterally spaced from each other upon inflation.

FIGS. 13 and 14 respectively illustrate side and cross-sectional viewsof an elongate shaft 1326, 1426 of a perfusion catheter, as constructedin accordance with at least one embodiment. The elongate shaft 1326,1426 can include a lumen 1430 extending from a proximal portion 1332 toan inflation port for providing inflation fluid to, or withdrawinginflation fluid from, a distal end of a distal balloon. The elongateshaft 1326, 1426 can extend a length 1374 of 100 cm-200 cm and canpossess the qualities of compression rigidity along its longitudinalaxis, which facilitates advancement of the perfusion catheter through apatient's vascular system, and good distal flexibility, which enhancesmaneuverability of catheter through directional changes of the vascularsystem and prevents damage to the vessel walls as it is being inserted.Portions of the elongate shaft 1326, 1426 can include a PTFE coating1376 to facilitate its advancement through the patient's vascularsystem.

These qualities are achievable in a variety of ways. In an example,proximal 1332 and intermediate 1338 portions of the elongate shaft 1326,1426 can include a stainless steel hypotube 1377, 1477, and the distalportion 1334 can include a stainless steel support wire 1379, 1479 ortube that is connected for a length 1375 to the intermediate portion.The support wire 1379, 1479 can help transmit forces applied by atreating clinician to either advance or retract the balloon during atreatment procedure. The support wire 1379, 1479 can range in lengthfrom 10 cm-20 cm and can be secured to the hypotube 1377, 1477 via alaser weld. The support wire 1379, 1479 can extend to a location distalto the balloon or can terminate between the balloon's proximal anddistal portions. In another embodiment, the elongate shaft 1326, 1426can be formed from a single piece of metallic or polymer tubing with aproximal portion that has an outer and inner diameter larger than anouter and inner diameter of a distal portion or with a proximal portionhaving greater wall thickness than a distal portion.

A means to affix an outer surface 1378 of the elongate shaft 1326, 1426and the flexible material of the balloon can be employed to withstandstresses associated with pressure changes of inflation and deflation ofthe balloon. It can be important that the affixing means create a fluidtight seal between the two materials and restrict any delamination alongthe seal line during prolong periods of working pressures. In anexample, portions of the elongate shaft 1326, 1426 coupled with theballoon can be covered with nylon (e.g., VESTAMID L2101) as part of theaffixing means. The materials can be joined by an adhesive process, suchas a cyanoacrylate, epoxy or urethane compounds, or joined by a heattreatment or pressure fit process that melts or welds the two materialstogether.

FIG. 15 illustrates a method 1500 of using a perfusion catheter in acoronary vessel for sealing a perforation or dissection or dilatingocclusive material while maintaining a passage.

At 1582, the method involves passing a perfusion catheter, including aballoon and an elongate shaft that is attached to the balloon, into ablood vessel until the balloon is positioned adjacent a perforation ordissection in a wall of the blood vessel.

At 1584, the method involves inflating the balloon to seal theperforation or dissection in the wall of the blood vessel. Inflation ofthe balloon can include urging fluid through a lumen of the elongateshaft and into the balloon to inflate a series of helical windings.

At 1586, the method specifies that the balloon, upon inflation, movesfrom a deflated configuration to an inflated configuration at which anouter surface of the balloon engages the wall of the blood vessel and aninner surface of the balloon's series of helical windings defines apassage.

At 1588, the method involves, after inflating the balloon, passing atreatment device at least partially through the passage. The treatmentdevice can be received in a distal-to-proximal direction or delivered ina proximal-to-distal direction.

At 1590, the method involves deflating the balloon by withdrawing fluidfrom the balloon in a distal-to-proximal direction of the balloon.

At 1592, the method involves retracting the perfusion catheter from theblood vessel. Additional or alternative steps may be incorporated intomethod 1500 in accordance with the present disclosure.

Closing Notes

The above Detailed Description includes references to the accompanyingdrawings, which form a part of the Detailed Description. The DetailedDescription should be read with reference to the drawings. The drawingsshow, by way of illustration, specific embodiments in which the presentcatheters and related methods can be practiced. These embodiments arealso referred to herein as “examples.”

The Detailed Description is intended to be illustrative and notrestrictive. For example, the above-described examples (or one or morefeatures or components thereof) can be used in combination with eachother. Other embodiments can be used, such as by one of ordinary skillin the art upon reviewing the above Detailed Description. Also, variousfeatures or components have been or can be grouped together tostreamline the disclosure. This should not be interpreted as intendingthat an unclaimed disclosed feature is essential to any claim. Rather,inventive subject matter can lie in less than all features of aparticular disclosed embodiment. Thus, the following claim examples arehereby incorporated into the Detailed Description, with each examplestanding on its own as a separate embodiment: In a first example, aperfusion catheter can include an inflatable balloon coiled in a helicalmanner around a central axis into a series of windings. An inner surfaceof the series of windings, when inflated, can define a passage throughthe inflatable balloon. The catheter can also include an elongate shaftextending from a proximal portion to a distal portion, having an innersurface that defines a lumen for providing inflation fluid to, orwithdrawing inflation fluid from, a distal end of the inflatableballoon. The catheter can further include a guidewire support tubeincluding a lumen, separate from the lumen from the elongate shaft andthe passage through the inflatable balloon, for receiving a guidewire.

In some examples, the perfusion catheter can optionally be configuredsuch that the guidewire support tube is inset in the inner surface ofthe series of windings. In some examples, the perfusion catheter canoptionally be configured such that an outer surface of the elongateshaft and the distal end of the inflatable balloon are affixed by a heattreatment process such that the shaft's lumen is in fluid communicationwith an interior of the balloon. In some examples, the passage can havea diameter ranging from 2 mm-6 mm and a length ranging from 10 mm-50 mm.In some embodiments, the elongate shaft can be eccentrically positionedrelative to the inflatable balloon such that the elongate shaft does notprotrude radially into the passage. In some examples, a proximal portionof the inflatable balloon can wrap around the elongate shaft, such thatthe proximal portion is sealed. In some examples, the guidewire supporttube and the elongate shaft can be inset in the inner surface of theseries of windings. In some examples, the inflatable balloon can beconfigured to deflate in a distal-to-proximal direction. In someexamples, the inflatable balloon can include concentric inner and outertubes, a polymer of the inner tube can be cross-linked, a polymer of theouter tube can be non-cross-linked, and the polymer of the inner tubecan have sufficient radial stiffness to resist bursting when exposed toinflation pressure. In some examples, adjacent windings of the series ofwindings can be stacked against and bonded to each other throughadhesive properties of the polymer of the outer tube when heated. Insome examples, a distal portion of the guidewire support tube canprotrude distally beyond the distal end of the inflatable balloon by 2mm-8 mm.

In accordance with some examples, a method can involve passing aperfusion catheter, including a balloon, and an elongate shaft that isattached to the balloon, into a blood vessel until the balloon ispositioned adjacent a perforation or dissection in a wall of the bloodvessel. The method can also involve inflating the balloon to seal theperforation or dissection in the wall of the blood vessel includingurging fluid through a lumen of the elongate shaft and into the balloonto inflate a series of helical windings of the balloon. The balloon,upon inflation, can move from a deflated configuration to an inflatedconfiguration at which an outer surface of the balloon engages the wallof the blood vessel and an inner surface of the balloon's series ofhelical windings defines a passage. After inflating the balloon, themethod can involve passing a treatment device at least partially throughthe passage, including receiving, in a distal-to-proximal direction, ordelivering, in a proximal-to-distal direction, a treatment device. Themethod can also involve deflating the balloon by withdrawing fluid fromthe balloon in a distal-to-proximal direction of the balloon, andretracting the perfusion catheter from the blood vessel.

In some examples, passing the perfusion catheter into the blood vesselcan include advancing a guidewire through a guidewire support tube,which is separate from the lumen of the elongate shaft and the passagedefined by the balloon's series of helical windings. In some examples,passing the perfusion catheter into the blood vessel can includeadvancing a guidewire through a guidewire support tube, which is insetinto the inner surface of the balloon's series of helical windings. Insome examples, inflating the balloon can include dilating occlusivematerial accumulation within the wall of the blood vessel. In someexamples, inflating the balloon can involve urging the fluid into theballoon in a distal-to-proximal direction of the balloon. In someexamples, deflating the balloon and retracting the perfusion cathetercan occur simultaneously. In some examples, inflating the balloon caninclude inflating the balloon to a pressure between 2 atm-20 atm,inclusive. In some examples, delivering the treatment device to thetreatment site or distal to the perforation or dissection can includeguiding the treatment device along a path offset from an axis of theelongate shaft. In some examples, inflating the balloon can involveurging the fluid through a fluid connection at a distal end of theballoon and a distal end of the elongate shaft.

Certain terms are used throughout this patent document to refer toparticular features or components. As one skilled in the artappreciates, different people may refer to the same feature or componentby different names. This patent document does not intend to distinguishbetween components or features that differ in name but not in function.

For the following defined terms, certain definitions shall be appliedunless a different definition is given elsewhere in this patentdocument. The terms “a,” “an,” and “the” are used to include one or morethan one, independent of any other instances or usages of “at least one”or “one or more.” The term “or” is used to refer to a nonexclusive or,such that “A or B” includes “A but not B,” “B but not A,” and “A and B.”All numeric values are assumed to be modified by the term “about,”whether or not explicitly indicated. The term “about” generally refersto a range of numbers that one of skill in the art would considerequivalent to the recited value (e.g., having the same function orresult). In many instances, the term “about” can include numbers thatare rounded to the nearest significant figure. The recitation ofnumerical ranges by endpoints includes all numbers and sub-ranges withinand bounding that range (e.g., 1 to 4 includes 1, 1.5, 1.75, 2, 2.3,2.6, 2.9, etc. and 1 to 1.5, 1 to 2, 1 to 3, 2 to 3.5, 2 to 4, 3 to 4,etc.). The terms “patient” and “subject” are intended to includemammals, such as for human or veterinary applications. The terms“distal” and “proximal” are used to refer to a position or directionrelative to the treating clinician. “Distal” and “distally” refer to aposition that is distant from, or in a direction away from, the treatingclinician. “Proximal” and “proximally” refer to a position that is near,or in a direction toward, the treating clinician.

The scope of the invention should be determined with reference to theappended claims, along with the full scope of equivalents to which suchclaims are entitled. In the appended claims, the terms “including” and“in which” are used as the plain-English equivalents of the respectiveterms “comprising” and “wherein.” Also, in the following claims, theterms “including” and “comprising” are open-ended; that is, a device,kit or method that includes features or components in addition to thoselisted after such a term in a claim are still deemed to fall within thescope of that claim. Moreover, in the following claims, the terms“first,” “second” and “third,” etc. are used merely as labels, and arenot intended to impose numerical requirements on their objects.

The Abstract is provided to allow the reader to quickly ascertain thenature of the technical disclosure. It is submitted with theunderstanding that it will not be used to interpret or limit the scopeor meaning of the claims.

What is claimed is:
 1. A perfusion catheter, comprising: an inflatableballoon coiled in a helical manner around a central axis into a seriesof windings, an inner surface of the series of windings, when inflated,defining a passage through the inflatable balloon; and an elongate shaftextending from a proximal end to a distal end and having an innersurface that defines a lumen for providing inflation fluid to, andwithdrawing inflation fluid from, the inflatable balloon; wherein thelumen of the elongate shaft is in fluid communication with an interiorof the inflatable balloon solely at a distal end of the inflatableballoon such that inflation fluid is added and removed exclusively atthe distal end of the inflatable balloon.
 2. The perfusion catheter ofclaim 1, wherein the elongate shaft includes an inflation port locatedat the distal end of the elongate shaft, the inflation port configuredto provide inflation fluid to, and to withdraw inflation fluid from, thedistal end of the inflatable balloon.
 3. The perfusion catheter of claim1, wherein a proximal end of the inflatable balloon is wrapped aroundthe elongate shaft to seal the proximal end of the inflatable balloon.4. The perfusion catheter of claim 1, wherein the inflatable balloon isconfigured to be deflated in a distal-to-proximal direction.
 5. Theperfusion catheter of claim 1, wherein the elongate shaft longitudinallyspans a length of the inflatable balloon.
 6. The perfusion catheter ofclaim 1, wherein the series of windings of the inflatable balloonsurround the elongate shaft.
 7. The perfusion catheter of claim 1,further comprising: a guidewire support tube including a lumen forreceiving a guidewire, the lumen of the guidewire support tube separatefrom the lumen of the elongate shaft and the passage through theinflatable balloon.
 8. The perfusion catheter of claim 7, wherein theguidewire support tube is inset in an inner surface of the series ofwindings.
 9. The perfusion catheter of claim 7, wherein the guidewiresupport tube and the elongate shaft are inset in an inner surface of theseries of windings.
 10. The perfusion catheter of claim 7, wherein adistal end of the guidewire support tube extends a distance beyond thedistal end of the inflatable balloon.
 11. The perfusion catheter ofclaim 10, wherein the distance is from 2 millimeters to 8 millimeters,inclusive.
 12. The perfusion catheter of claim 1, wherein an outersurface of the elongate shaft and the distal end of the inflatableballoon are affixed by a heat treatment process such that the lumen ofthe elongate shaft is in fluid communication with the interior of theinflatable balloon.
 13. The perfusion catheter of claim 1, wherein thepassage has a diameter ranging from 2 millimeters to 6 millimeters,inclusive, and a length ranging from 10 millimeters to 50 millimeters,inclusive.
 14. The perfusion catheter of claim 1, wherein the inflatableballoon includes concentric inner and outer tubes, a polymer of theinner tube is cross-lined, a polymer of the outer tube isnon-cross-linked, and the polymer of the inner tube has sufficientradial stiffness to resist bursting when exposed to inflation pressure.15. The perfusion catheter of claim 1, wherein adjacent windings of theseries of windings are stacked against and bonded to each other throughadhesive properties of a polymer of the inflatable balloon when heated.16. The perfusion catheter of claim 1, wherein the inflatable balloonhas a length in a range from 40 centimeters to 120 centimeters,inclusive, before being coiled into the series of windings.
 17. Theperfusion catheter of claim 1, wherein the series of windings of theinflatable balloon are configured to, when inflated, engage a vesselwall of a patient at a treatment site while allowing a flow of blood ormovement of a treatment device through the passage.
 18. The perfusioncatheter of claim 1, wherein the inflatable balloon is configured to bedeflated by applying a vacuum to a proximal manifold coupled with theproximal end of the elongate shaft.
 19. A perfusion catheter,comprising: an inflatable balloon coiled in a helical manner around acentral axis into a series of windings that are stacked against andbonded to each other, an inner surface of the series of windings, wheninflated, defining a passage through the inflatable balloon; and anelongate shaft extending from a proximal end to a distal end and havingan inner surface that defines a lumen for providing inflation fluid to,and withdrawing inflation fluid from, the inflatable balloon; whereinthe lumen of the elongate shaft includes an inflation port that is influid communication with an interior of the inflatable balloon in such away that inflation fluid is exclusively added and removed from thedistal end of the inflatable balloon.
 20. A perfusion catheter,comprising: an inflatable balloon coiled in a helical manner around acentral axis into a series of spaced apart windings that do not contacteach other, an inner surface of the series of windings, when inflated,defining a passage through the inflatable balloon; and an elongate shaftextending from a proximal end to a distal end and having an innersurface that defines a lumen for providing inflation fluid to, andwithdrawing inflation fluid from, the inflatable balloon; wherein thelumen of the elongate shaft includes an inflation port that is in fluidcommunication with an interior of the inflatable balloon in such a waythat inflation fluid is exclusively added and removed from the distalend of the inflatable balloon.